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1.
The aquifuge stability is the key to study the impacts of coal mining on the aquifer. Based on the geological conditions of a mine in Yili of Xinjiang, China, this paper has studied the stability evolution laws of clay aquifuge during extremely thick coal seam mining by similar material simulation experiment in the laboratory. For the water-swelling and expansion property of clay aquifuge, the reasonable proportion of the similar material is firstly determined by taking the uniaxial compressive strength and the permeability coefficient as core indexes. Then, the overlying strata movement coupled solid–liquid physical model is established. In addition, the aquifuge deformation, the water level changes of the aquifer, and the height of fracture zone in overburden are analyzed during the slice mining. The research results indicate that the clay aquifuge will gradually occur instability failure during the mining of the working face, and the aquifuge stability has the threshold effects. When the ratio of the vertical displacement of the aquifuge to the thickness is Dv/T?≤?58.0%, the ratio of the horizontal displacement to the thickness is Dh/T?≤?17.0%, and the height of fractured zone in overburden is below the aquifuge, the mining-induced fractures may be closed and the aquifuge stability could be maintained. If Dv/T?≥?75.0%, Dh/T?≥?23.9%, and the height of fractured zone in overburden is within the aquifuge, the fractures will develop and connect the aquifuge and the stability failure of the aquifuge will occur, which has a direct correlation with the mining height. 相似文献
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工作面回采过程中,覆岩破坏特征对于煤矿水灾害和瓦斯防治具有重要意义,为了进一步研究综放开采覆岩破坏特征。以山西某矿5.82m大采高工作面为试验面,采用分段注水、钻孔电视、地质雷达、微震监测探测覆岩破坏高度,对破坏过程进行了数值模拟研究,并对裂隙演化进行了相似模拟试验,同时对传统经验公式进行了修正,研究结果表明:综放开采垮落带发育高度为43.1m,断裂带发育高度为86.7m;垮落带、断裂带、导水断裂带各测试方法之间相差分别小于4.5%、7.1%、9.0%;工作面采动前,裂隙发育度低,而采动后,裂隙数量明显增多,发育度增加;近煤壁区域为裂隙聚集区,密度曲线呈“蛇”型分布;得到新的适合该矿地质条件下的覆岩导水断裂带发育高度经验公式。 相似文献
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综采一次采全高顶板导水裂缝带发育高度的计算公式及适用性分析 总被引：2，自引：0，他引：2
确定煤层顶板导水裂缝带高度可为顶板防治水、采掘工程布置、防水煤柱留设以及瓦斯抽采设计提供依据。采用井下仰孔注水测渗漏法,实测山西西山煤田镇城底矿8煤导水裂缝带高度为57.98 m,其中冒落带高度16.72 m,裂隙带高度41.26 m。依据实测结果并收集了8个矿综采一次采全高中硬覆岩下导水裂缝带高度数据,利用数理统计回归分析的方法,得出了适用于综采一次采全高中硬覆岩下导水裂缝带高度计算的经验公式,并与《煤矿安全规程》中相应经验公式进行对比分析,结果表明,该公式适用性好,而《煤矿安全规程》中有关公式应用于中厚煤层综采一次采全高开采条件预测,其误差较大。 相似文献
4.
Zhongchang Wang Chuan Wang Zechuan Wang 《Geotechnical and Geological Engineering》2018,36(5):3019-3028
The water inrush of roof induced by mining was related to the height of water flowing fractured zone under large-scale water bodies. Based on the drilling revealed stratum, the thickness of different overlying layers was obtained within the scope of Santaizi reservoir. The height of water flowing fractured zone of different workface on the outside of reservoir under the condition of fully mechanized level mining area was the prediction sample, the generalized analysis of sensitive factors that affected the development of water flowing fractured zone was carried on. The mining depth, dip angle of coal seam, mudstone ratio, compressive strength, mining thickness and the inclined length of the goaf were selected as the influence factors to predict the height of water flowing fractured zone. The height of water flowing fractured zone of unmined working face within the scope of Santaizi reservoir was obtained by objective entropy method. The index weight value of each influence factor was determined. The thickness of the different overlying rock layers above water flowing fractured zone was obtained. And the safety evaluation of water-inrush of unmined working face within the scope of Santaizi reservoir was studied. The important parameter and technical support were provided for the rational design and mining of the working faces under the reservoir. 相似文献
5.
D. Mukherjee V. A. Selvi J. Ganguly L. C. Ram R. E. Masto 《Journal of the Geological Society of India》2018,91(5):575-582
Coal contains abundant microbial genera which include archaebacteria. The study of archaea kingdom in coal mines is a significant tool for knowing the relationship between coal and archaebacteria, the major role in geochemical cycle and application for further coal bio–beneficiation. The present study related to exploration of archaebacteria and their habitat in coal mining area of Dhanbad with reference to their ecology and nutrient availability that have evolve to grow under extreme conditions. Total six different sites such as two underground coal mines (Sudamdih shaft and Chasnalla underground mine), two opencast coal mines (Chandan project and Bhowra abandoned mine), Jharia mine fire and Sudamdih coal washery of Dhanbad was selected. Seven gram negative obligate anaerobic bacteria were isolated from the selected sites. The isolated species were rod and cocci shaped and the colony was round, smooth, off white in colour and with entire margin and little are cluster of cocci in shape. The isolated species were identified as Methanococcus spp, Methanobacterium spp and Methanosarcina spp. Apart from that two thermoacidophilic sulfur oxidizing bacteria Sulfolobus spp was also isolated from Jharia Coal Mine Fire. The physicochemical and biological characterization of the habitat was also studied for the entire selected area. 相似文献
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Monitoring of strata control parameters and behaviour of a powered support was carried out during an experimental trial of a mechanized longwall sublevel caving face for exploitation of a 7.5m thick coal seam. Field observations indicated that the requirement of support density for underwinning of top coal by sublevel caving under intact strata is different from that for underwinning under broken and fractured rock mass. Analysis of the leg closure observations and support resistance variations during different mining cycles showed rapid increase of the setting load density of the support in relation to the yield load density. This resulted in a large amount of leg closure during mining cycles of the sub level caving face under broken rock strata. Due to operational constraints, the field observations could not provide enough information to visualize the behaviour of the overlying rock strata. Simulation of the field conditions was therefore performed on a physical model to bridge this gap of information. Results of laboratory investigations on the physical model are combined with those of the field to explain the critical behaviour of the support system during sublevel caving under broken rock strata. 相似文献
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林南仓属于低瓦斯矿井,但存在高瓦斯区域。煤层和采空区是瓦斯的主要来源,尤以采空涌出量大,给煤矿生产和安全带来了极大隐患。通过在1129综采工作面风道施工高位瓦斯孔,把钻孔打到采空区一侧煤层顶板以上冒落裂隙带内,用钻孔进行瓦斯抽放,使采空内的瓦斯通过裂隙带沿钻孔抽出,有效降低综采工作面瓦斯浓度,保证综采工作面正常回采和安全生产。 相似文献
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导水裂隙带发育高度是矿井水害预测的重要技术参数之一。以彬长矿区文家坡煤矿4103工作面为研究对象,利用井-地联合微震监测技术对顶板导水裂隙带发育特征进行研究。研究结果表明:深埋煤层开采时,微震事件超前工作面回采位置发育,超前影响角最大为35°,最小为28°;断层的存在降低了覆岩稳定性,相较于正常基岩,更易在回采影响下发生应力集中和破坏;断层加大了微震事件发生的超前距,而采空区则使微震事件的高密度区向其所在部位发生偏移,加剧覆岩破坏程度,增大导水裂隙带发育高度;垂向上,4103工作面监测区内的微震事件高密度区域主要集中在高程+400~+520 m,结合微震事件数量和能量分布特征,判定4103工作面垮落带发育高度为50 m,垮采比13.16,导水裂隙带发育高度为117 m,裂采比为30.79。该成果可为彬长矿区类似煤矿深埋煤层顶板导水裂隙带发育高度研究及顶板水防治提供重要依据。移动阅读 相似文献
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21181综放工作面突水分析与治理 总被引：1，自引：1，他引：0
通过对21181综放工作面的突水特征与突水水质检测资料的分析,以及开采导水裂隙带高度的计算,得出了工作面突水原因——采煤后形成的导水裂隙带已波及到了上覆侏罗系上统巨厚砾岩含水层,通过运用合理的防治方案．为今后综放工作面预防水害打下了基础。 相似文献
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采用相似模型试验和数值模拟相结合的方式,分析了奥陶系石灰岩推覆体含水层下煤层开采的覆岩破坏及地表沉陷 特征。经验公式计算,相似模型试验和数值模拟的对比分析表明：该特殊地质条件下,不考虑渗流场影响时,垮落带高度 为采厚的2.2~4.5倍,导水裂隙带高度为采厚的14.0~19.1倍;渗流场的存在使导水裂隙带及垮落带高度增加,此时垮采比为 4.8,裂采比为20.6。因此,从偏安全的角度考虑,煤层的实际开采过程应考虑渗流场的影响,以渗流场-应力场耦合作用 下的导水裂隙带高度作为安全煤（岩）柱合理留设的依据。 相似文献
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为了研究黄陇煤田综采放顶煤（综放）采煤工艺条件下的导水裂缝带高度及其发育规律,系统收集区内各矿井实测数据资料,采用数理统计和回归分析方法研究导水裂缝带高度与工作面宽度、煤层埋深以及采高的相关关系。研究结果表明:工作面宽度小于240 m且煤层采高为8.5~9.5 m时,软弱覆岩裂采比和导水裂缝带高度恒大于中硬覆岩;工作面宽度大于90 m且煤层采高大于14.5 m时,软弱覆岩裂采比和导水裂缝带高度恒小于中硬覆岩。综放软弱顶板裂采比和导水裂缝带高度随采高增大均呈单峰状,裂采比是采高的二次函数,导水裂缝带高度是采高的三次函数。裂采比最大为30.63倍,拐点处采高3.56 m;导水裂缝带高度最大为239.97 m,拐点处采高10.41 m。由拐点向两侧采高分别减小或增大时,裂采比和导水裂缝带高度均逐渐减小。综放中硬顶板裂采比和导水裂缝带高度受工作面宽度和煤层采高的共同影响。在工作面宽度一定时,裂采比随着煤层采高增大而逐渐减小且变化幅度越来越小,大致趋于[11.00,14.30]数值区间;在煤层采高一定时,工作面宽度越大裂采比越大。导水裂缝带高度随着工作面宽度和煤层采高增大而增大。 相似文献
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侧向支承压力分布、资源回收率以及煤柱和巷道的稳定性是大采高综放面区段煤柱宽度留设要兼顾的因素,为了确定大采高综放面区段煤柱宽度,以某矿8103面为工程背景,首先,采用理论计算和现场应力监测等方法确定大采高综放工作面倾向支承压力分布规律,得出应力降低区宽度约为8 m,原岩应力区为巷帮侧28 m外。其次,采用工程类比方法确定大采高综放工作面巷帮外侧煤体严重破裂区宽度约为4 m。最后,采用FLAC3D数值软件分析了下区段工作面回采时窄煤柱（6、8 m）和宽煤柱（28、30 m）的应力场、位移场及塑性区特征,获得不同煤柱宽度时巷道和煤柱力学特征。研究表明：当煤柱宽度6 m和8 m时,在采动支承压力下煤柱几乎无承载能力,且巷道变形量较大;当煤柱宽度28 m和30 m时,在采动支承压力下煤柱中央仍有一定的弹性核,煤柱保持稳定且巷道变形量较小。综合考虑资源回收、巷道稳定性、次生灾害控制等因素,确定大采高综放工作面区段煤柱宽度为28 m。 相似文献
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The recent development of the coalbed methane (CBM) industry has a significant role in advancing hydraulic fracturing theory and technology. However, further development requires a better understanding of how fractures influence reservoir permeability. In situ stress data from 54 CBM wells in the southern Qinshui Basin, China, were obtained by the injection/falloff test method to analyse the effect of in situ stress on the permeability of the CBM reservoir. The types of in situ stress states were classified, and the coal reservoir permeability under different in situ stress states was analysed. The results indicate that the maximum horizontal principal stress (σH), minimum horizontal principal stress (σh) and vertical principal stress (σv) all have positive linear relationships with the coal seam burial depth. Three in situ stress states were observed from the shallow to deep regions of the CBM reservoir in the study area: σH?>?σh?>?σv, σH?>?σv?>?σh and σv?>?σH?>?σh, which account for 9, 76 and 15% of the test wells, respectively. Coal reservoir permeability decreases with increasing horizontal principal stress, whereas it first decreases with increasing σv, then increases and finally decreases. The variation in permeability with σv is due to the conversion of the in situ stress states. Coal reservoir permeability has obvious differences under different in situ stress states. The permeability is the largest when σv?>?σH?>?σh, followed by σH?>?σh?>?σv and smallest when σH?>?σv?>?σh. The permeability differences are caused by the fracture propagation shape of the rock strata under different in situ stress states. 相似文献
17.
以大同矿区同忻煤矿为例,利用关键层理论、物理探测技术和数值模拟,分析双系煤层开采形成的覆岩运动与破坏规律。研究结果表明：（1）石炭二叠系煤层工作面推进至193 m时,覆岩裂隙带发育高度达到最大为174.7 m;（2）物理探测得到3-5^#煤层开采引起的覆岩垮裂带高度约为180 m,综合理论计算与现场实测,确定覆岩裂隙带发育高度与采厚之比为11.7-12.0;（3）侏罗系煤层开采引起的底板破坏及双系间覆岩软弱夹层的缺失为双系煤层采空区联通进一步提供了条件;（4）侏罗系煤层的开采影响石炭二叠系煤层工作面超前支承压力的分布规律,当石炭系煤层工作面位于侏罗系煤层遗留煤柱下方时,超前支撑压力较无采空区时增大12.4%;（5）研究成果揭示了双系开采相互影响关系,为采取安全开采措施、减弱双系开采相互影响程度提供了科学依据。 相似文献
18.
Lei Wang Tao Wei Nan Li Shen-shen Chi Chuang Jiang Su-yang Fang 《Environmental Earth Sciences》2018,77(21):740
Probability integral method is an official prediction method for mining subsidence in China. However, how to obtain the probability integral method parameters based on the measured data is the premise of realizing the accurate prediction of the probability integral method. Simulated annealing (SA) is an effective nonlinear optimization algorithm that has recently been introduced into the mining subsidence field to obtain the parameters of the probability integration method. To solve the problems of slow convergence speed and easily falling into the local optimal solution in the method of parameters inversion in probability integral method based on SA (MPIPIMSA), the method of parameters inversion in probability integral method based on quantum annealing (MPIPIMQA) is proposed by combining the quantum fluctuation mechanism and simulated annealing theory. The simulation experimental results show that MPIPIMQA is superior to MPIPIMSA in the accuracy and stability of parameters, and MPIPIMQA has a stronger anti-interference ability for local losing observation points, random errors and gross errors in observation data. Finally, the parameters of probability integral method for the 1414(1) working face of the Guqiao Coal Mine in Huainan mining area were obtained by using MPIPIMQA, namely, q?=?0.9916, tanβ?=?1.9277, b?=?0.4190, θ?=?84.3381, Su = ??7.3715, Sd = ??14.7126, Sl = 59.0695, and Sr = 32.6381, and the fitting error is 106.8863 mm. The research results have important reference values for accurate inversion of probability integral parameters. 相似文献
19.
煤炭开采引起覆岩破断及地表下沉,覆岩及地表运移规律可反映裂隙带高度的动态演化过程。因地表下沉滞后于煤炭开采,对于废弃采空区,长期压实作用导致裂隙带高度较采动期间有所降低。基于地表点下沉速度的阶段特征将裂隙带高度的演化过程分为2个阶段,第1阶段裂隙带发育对应岩层破断逐步向上传递的过程,第2阶段裂隙带高度降低对应离层及裂隙闭合、断裂岩层受压后变形回弹及破碎岩体自然压实的过程。着眼于压实作用对裂隙带高度的影响,根据煤层采厚、垮落带和裂隙带岩层变形量及地表下沉值之间的定量关系,建立了第2阶段裂隙带高度预测模型,并结合太平煤矿实测结果进行验证,采用控制变量法分析了单一因素影响下废弃采空区裂隙带高度的演化特征。结果表明：废弃采空区裂隙带高度受控于垮落带块体强度、垮落带初始碎胀系数、采动期间裂隙带高度最大值及对应的垮落带高度、煤层埋深、地表最终下沉量等因素,太平煤矿采后15 a的裂隙带高度实测值11.36～13.00 m与理论预测值12.75 m吻合度较高,模型的可靠性得到验证。最后,应用此预测模型对武安煤矿（关停矿井）2002－2003年采空区裂隙带高度开展理论计算,结合地空瞬变电磁探测确定了地面瓦斯抽采钻孔理想的终孔位置并成功开展了地面钻孔瓦斯抽采试验。 相似文献
20.
研究开采上限对煤矿开采具有十分重要的意义,它可以最大程度地开采压滞的煤炭资源,缓解当前大部分煤矿采掘接替紧张的局面。以田庄矿N2601工作面为例,根据已有水文地质资料以及邻近矿井资料,分析了开采区充水条件及底部含水层的赋水特性;采用数值模拟方法,根据上覆岩层的塑性应变情况,分析了冒落带与导水裂隙带的高度范围,最后综合数值模拟结果与“三下”开采规程的要求确定了该矿的开采上限。 相似文献